p1 - matter (from PMT) Flashcards
approximately what proportion of the total radius of an atom is the radius of the nucleus?
1/10,000
define sublimation
when a substance transitions from a solid straight to a gas without transitioning into a liquid in between
what is the internal energy of a substance?
-energy stored by the particles
-sum of the total kinetic and potential energies that make up the system
describe the motion of molecules in a gas
constant random motion
describe the force that the pressure of a gas exerts on the walls of its container
-net force acts at right-angles to the container’s surface
-magnitude of the force increases as pressure increases
why does the temperature of air inside a bike pump increase when it is pumped?
-work is done on a gas when it is compressed
-doing work on a gas increases its internal energy, so also increases the average kinetic energy of the molecules
-temperature increases with an increase of average kinetic energy
why does atmospheric pressure decrease as you move higher above the earth’s surface?
atmospheric pressure at a point is equal to the weight of the air in the column above that point, as you move higher above the Earth the amount of air in said column decreases - resulting in less weight above and as a result less pressure at the point
what does an object in a fluid experience as a result of pressure?
forces at right angles to all of its surfaces
why does pressure in a fluid increase with depth?
because it is caused by the gravitational forced on the fluid. the deeper you go, the greater the weight of the water above you, and so a higher force and pressure
define upthrust
the upwards force that an object experiences in a fluid as a result of a greater pressure below the object than above it
when will an object float
when an object’s upthrust equals its weight
when you submerge an object in a liquid, what is the upthrust acting on the object equal to?
the weight of the volume of liquid displaced as it is submerged
what can be said about the density of an object that sinks in water?
the objects density is greater than the density of water
